Inadequate intakes of fruit, juice, and vegetables (FJV) and high intakes of dietary fat are associated with increased risks for several cancers. Children's current FJV and fat intakes do not meet recommended guidelines and national data indicate a decline in children's fruit consumption through the school years. Previous school interventions targeted elementary schools where students only have the choice of the school lunch meal. When students move to middle schools and beyond, they have access to competitive foods at snack bars. These foods are usually high in fat and do not include many FJV. This research proposes to develop, implement, and evaluate an environmental intervention (increasing FJV availability and accessibility) and a cafeteria FJV marketing program in middle school cafeterias to increase FJV consumption, and to assess the effect of personal and social influences on who changes. Focus groups discussions will be conducted with middle school students, teachers, and school food service staff to design and evaluate the availability and marketing program. The intervention will be implemented in two phases following an initial two-month baseline monitoring period. First the availability and accessibility of FJV and low fat foods will be increased in the cafeteria snack bar for three months. This will be continued for another two months, adding the FJV marketing program. During the final two months, the intervention component will be withdrawn; observations will continue to see if school practices and snack bar food selections return to baseline. Weekly sales of FJV and low fat foods will be collected during this period to monitor intervention results. Consumption data will be obtained through daily observations of student lunches during the entire study period. This design will allow separate tests of the effect of increased FJV availability alone versus increased availability with a social marketing program, and assess personal and social environmental mechanisms of change. Successful dietary behavior change interventions in middle school cafeterias will promote the adoption of healthy cancer preventive dietary behaviors. Positive findings from this study should be applicable to middle schools where snack bars are available.